Electrically operated stapling devices and associated control circuits for same are known in the prior art. For example, Wines and Power U.S. Pat. No. 3,971,969 entitled "Electrically Operated Stapling Device" discloses means for applying at least two unidirectional drive pulses derived from an input AC voltage for driving a single staple per switch activation. However, such device requires: two switches 23 and 37; and two silicon controlled rectifiers 71 and 86. Further, such device does not provide one pulse per staple at variable intervals nor does it provide either one and only one pulse per switch activation or two and only two pulses per switch activation.
Objects of the present invention are therefore to provide a silicon controlled rectifier trigger circuit which:
Is readily adaptable to an electric stapler or an electric brad driver and which will deliver one and only one staple or brad per switch activation;
If the switch is maintained activated, further drive pulses are delivered at intervals of less than a second to many seconds;
The drive pulse interval can be made adjustable by utilizing a potentiometer;
Utilizes only one activation switch;
Utilizes only one silicon controlled rectifier;
A train of drive pulses can be delivered to the load, each pulse being approximately one-half cycle long and at intervals of from less than a second to many seconds;
Provides two drive pulses per switch activation; and
Provides one drive pulse per switch activation.